BBs, Martins & Hawks

[Guest]

This week-end at the lake, I checked on my bluebird nest and the two hatched babies were gone. Originally, there had been 6 eggs but two only hatched. When I did a nest check there were only 2 eggs instead of the four I expected in the same nest and the nest had not been damaged as if a predator had been there. As soon as the "children" leave do the BBs start another family in the same nest? Also, what would have happened to the other 2 eggs?

When I got to the lake this week-end I had a great surpirse. I had picked up 5 SYs; 3 females and 2 males. I now have 6 ASY pairs, 2 SY pairs and 1 extra female. Hope she finds a mate this week. One SY pair chose the Coates Watersedge and had no problem negotiating the SREHs. They are very diligent nest builders and act much more mature than SYs - hope they have a successful nesting season. The other SY pair chose the Heath( ) and finally began nest building today.

Out of 6 ASY pairs, there are 5 that have been building nests for about 2-1/2 weeks now, but one that still has only 4 dead oak leaves. That pair may not be successful, but will have to admit the male found a mate later than the other pairs.

Last but not least - The Hawk - My husband and his brother turned just in time to see that a hawk had landed on the ground approxinately 10 ft. from the gourd rack. From the way they described him he could have been a broad shouldered hawk? His underside was white and I think they said he had brown on him. Why did he just land on the ground instead of trying to pluck a martin from the top of the gourd rack? Of course, the martins took to the air squawking. My husband scared him off and he went about his business.

Thanks for info you can provide me.


Lanell

[Guest]

Hi, Lanell!

As I recall, your BB/PM housing is at your weekend home, and you aren't able to monitor during the week, right?

Your BB nest had 6 eggs originally? And then only 2 hatchlings? Is this correct? If so, I would say that something removed the other eggs. A HOSP will usually smash up the whole clutch, and a snake would probably eat them all, but a house wren can and will remove one or more eggs, leaving the others undisturbed. Are your boxes in or near wren territory?

Also, bluebirds can remove infertile or defective eggs from their own nest, so if 2 hatched and the rest of the eggs were bad, perhaps Mom and Pop removed the others. I had my first 6 egg clutch this year. One egg hasn't hatched, and Mama has rolled it off to the side. If she doesn't remove it herself, I will pull it out tomorrow.

How long between the eggs hatching and the babies being gone? Nestling phase in bluebirds ranges between 16 and 23 days - 18 to 19 is what I usually see. If it was less than 2 weeks, then I would say something happened to your babies. Again, snake is one thought.

As for the hawk, many hawk species have brown backs and light undersides - do you mean BROAD-WINGED or RED-SHOULDERED? I am not aware of any "broad-shouldered" hawk. Both broad-winged and red shouldered hawks are Buteos, and their main diet is not birds, but small mammals, amphibians and reptiles, although they are not above taking smaller birds. Because of their shape and their heavy bodies, they are not as aerodynamic as the Accipter (Cooper's, Sharp-shinned) hawks or the falcons, so are less of a threat to martins.

Congrats on your martins!

[John Atteberry]

Hello Lanell,
That is great news to hear your colony is growing!!!! I agree with Dr. Kathi on the rest of your post! Good luck and keep us posted on your colony! John!

[Guest]

Thanks, Dr. Kathi and John. Yep, the colony is growing and it has been so much fun watching. I'm hoping with last Friday's influx of SYs I will pick up a few more pairs. Would love to make it 10 pairs this year. Red shouldered or broad winged is what I meant about the hawk. Hopefully he is not a great threat to the martins.

Thanks for the input on the bluebirds. This is my first year to host them. I will learn more about them as time goes on.

Hope you are havinag a great season.


Lanell